FROMLIST: ARM: kprobes: rewrite test-arm.c in UAL

Clang's integrated assembler only accepts UAL syntax, rewrite the
instructions that were changed by RVCTv2.1.  The document "Assembly
language changes after RVCTv2.1" was very helpful.

  .syntax unified

directive is added, since -masm-syntax-unified is unreliable for older
but supported versions of GCC. See also:

commit fe09d9c6 ("ARM: 8852/1: uaccess: use unified assembler language syntax")

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://developer.arm.com/documentation/dui0473/c/writing-arm-assembly-language/assembly-language-changes-after-rvctv2-1
Link: https://github.com/ClangBuiltLinux/linux/issues/1271
Bug: 141693040
Link: https://lore.kernel.org/linux-arm-kernel/20210211025149.3544593-3-ndesaulniers@google.com/
Change-Id: Icbd266fce538460c64900e2fa0f032561e208363